Hi,
My daughter, 6 months, is diagnosed with sinus tachycardia, little enlarged heart and LV little dilated. While sleeping her heart rate now is sometimes around 180 and sometimes 98 less early it was 217 max while active. When we did the Echo, at the age of one month EF was 43% and at 3 months EF was 56% and now it is measured as 51%. All these 3 echoes are done by different doctors. Is this EF is normal and will there be any chance of developing this into cardiomyopathy? Her mother is also having tachycardia and is asymptomatic like the daughter. During pregnancy, had tachycardia and did fetal echo.
Based on the doctors advise my daughter is not under any medication, as they could not find the reason behind the tachycardia.
What could be the reason behind the tachycardia and if the heart continue to beat like this will there be any chance of increasing the LV dilation? She is putting normal weight, and all other functions of heart is normal except this tachycardia, LV dilation, little enlarged heart and EF.

While doing the TFT we found that Free T3 is on the higher side. The reading is as follows.

Free T3 = 6.7pmol/l
Free T4 = 16.8 pmol/l
TSH = 1.85uUl/ml.
After delivery , from hospital they have done the TSH from cold blood on 29 may 2011. The result was 13.01 miu/L.

It will be impossible to determine what the cause of your child's rapid heart rate is on this website. There are comments to be made, however, on multiple issues. First, the fact that the tachycardia was noted even in fetal life and has persisted for 6 months may be contributing to the heart enlargement. The longer that the heart beats too fast, the more likely that it will stress the heart. Second, one must explore all potentially treatable options here; so if there are even borderline abnormalities of the thyroid functions, that needs to be evaluated by an endocrinologist. Additionally one should evaluate the baby's blood and urine for high levels of catecholamines. Rarely there are small tumors that can secrete high levels of hormones that can raise the heart rate. Third, if the ejection fraction was measured at 43%, that is low and is not normal. A normal ejection fraction in a young child with a structurally normal heart should be 55-65%. Although it is consoling that more recent ejection fractions have been higher, this certainly could point to your child having a predisposition to cardiomyopathy. Last, there are some unusual cardiac arrhythmias that can LOOK like sinus tachycardia on ECG, but are actually abnormal rhythms: these include ectopic atrial tachycardia and sinus node re-entry tachycardia. If your child has one of these and they go untreated, the stress on the heart will continue. It is great to hear that your child is asymptomatic and gaining weight, but the heart enlargement is worrisome. If you have access to a pediatric electrophysiologist, I would suggest getting a second opinion.

The small patent foramen ovale is an opening between the upper heart chambers that all babies are born with. In most cases it closes on its own within the first 1 to 2 years of life, and does not cause any symptoms. So if the echo was done while the baby was young, this is likely a normal variant.

Can i have your email address, if possibile, to send the medical report of my daughter for your opinion? alternativly if you can send a mail to "***@****" , it will be of great help. Though the doctor from India advised to give the Digoxin (0.02mg BID) to her, we stopped it as per the advise of the doctor from Oman.We gave her digoxin for approx 15 days. Now for the past 4 months she is not under any medication.

As per endocrinologist, since TSH and Free T4 are under normal range, no need for any medication. As per them they will consider medication only if there is a variation in Free T4 or TSH from normal range.

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